“Red sky at night, sailor’s delight. Red sky at morning, sailor’s warning.” I can remember my mom telling me about that phrase when I was quite young. She told me that if the sky was red at morning, then it was most likely going to rain that day. However, if the sky was red at night and then clear in the morning, it wasn’t going to rain.
That’s all I needed to know to be satisfied. It made sense once she got it explained without all the stumbling and muttering.
However, when I came across the phrase on the Internet, it seems to say it is “Red sky at night, shepherd’s delight. Red sky at morning, shepherd’s warning.”
It most likely doesn’t make a difference, but I had just never heard shepherd in the phrase. I can see that either profession would be curious about the weather. After all, the sailor want it to be clear so the waters stay clam and they can sail. The shepherds want to be able to have their flocks out in the fields.
While there are all sorts of crazy ideas and rhymes about predicting the weather, this one is less so a crazy idea, and more meteorologically based. It may not always be true, but it can work at times.
This has to do with the spectrum and the different colors of light being dispersed, refracted, and reflected as well as the positioning of clouds. Red is the color with the broadest wavelength and there are times that the red can easily appear in the sky because of this, though it is usually blue that appears (a quick answer to “why is the sky blue?”).
Red can reflect of off the clouds and being that the sun rises in the east, the reflection of red can help.
The night and day thing is at least true over in England because at night, the red would be reflecting from clouds that are not near the sun and thus the clouds would be headed away. However, in the morning, the red would be reflected from clouds that have not yet reached that location and that could easily mean rain.
While this explains the idea of the phrase, sources of the phrase have not been given.
It is likely that the phrase was passed down orally for many generations.
A written version of the phrase appears in 1395 in Matthew XVI of the Wyclif Bible. It says, “The eeuenynge maad, ye seien, It shal be cleer, for the heuene is lijk to reed; and the morwe, To day tempest, for heuen shyneth heuy, or sorwful.” This is from the unauthorized version and the authorized version gives a more familiar way of saying the phrase, “When it is evening, ye say, It will be fair weather: for the sky is red. And in the morning, It will be foul weather to day: for the sky is red and louring.”
It later appears in 1593 in Shakespeare’s Venus & Adonis. It says, “Like a red morn, that ever yet betoken’d wreck to the seaman – sorrow to shepherds.”
There is no record of how the current rhyme came to be, but as can be seen, it is a very old idea.
Martin, Gary. “Red sky at night”. The Phrase Finder. June 14, 2010 http://www.phrases.org.uk/meanings/red-sky-at-night.html>.